新疆西准噶尔晚泥盆世法门期的苔藓虫动物群及其形态特异性和古环境意义*

本文重新研究了产自新疆西准噶尔晚泥盆世法门期洪古勒楞组和铁列克提组的苔藓虫动物群, 重点关注其形态学特征和古生态学意义。该苔藓虫动物群由隐口目(Cryptostomata)、窗格苔藓虫目(Fenestrata), 变口目 (Trepostomata)和泡孔目(Cystoporata)组成。优势类群隐口目苔藓虫是具有中轴或中板的细枝状和双叶状群体。 它们的虫室具有加厚的外区体壁, 弯曲强烈的自虫室, 数量众多的大虫室(metazooecia)或隐蔽虫室(tectizooecia), 以及径向刺突和/或棘状刺突。多样化的异虫室、刺突、自虫室等结构, 以及不同生长环境中的不同生态组合是新疆西准噶尔法门期苔藓虫成功演化的基础。洪古勒楞组下段和铁列克提组下部的苔藓虫动物群可以划分为三类生态组合(即: No. 1, No. 2和No. 3), 代表前滨—近岸—远岸的沉积环境。其中, 近岸环境的枝状—双叶状—网状苔藓虫组合的属种丰度、分异度最高。     

新疆西准噶尔晚泥盆世法门期的苔藓虫动物群及其形态特异性和古环境意义*

本文重新研究了产自新疆西准噶尔晚泥盆世法门期洪古勒楞组和铁列克提组的苔藓虫动物群, 重点关注其形态学特征和古生态学意义。该苔藓虫动物群由隐口目(Cryptostomata)、窗格苔藓虫目(Fenestrata), 变口目 (Trepostomata)和泡孔目(Cystoporata)组成。优势类群隐口目苔藓虫是具有中轴或中板的细枝状和双叶状群体。 它们的虫室具有加厚的外区体壁, 弯曲强烈的自虫室, 数量众多的大虫室(metazooecia)或隐蔽虫室(tectizooecia), 以及径向刺突和/或棘状刺突。多样化的异虫室、刺突、自虫室等结构, 以及不同生长环境中的不同生态组合是新疆西准噶尔法门期苔藓虫成功演化的基础。洪古勒楞组下段和铁列克提组下部的苔藓虫动物群可以划分为三类生态组合(即: No. 1, No. 2和No. 3), 代表前滨—近岸—远岸的沉积环境。其中, 近岸环境的枝状—双叶状—网状苔藓虫组合的属种丰度、分异度最高。     

Frasnian bryozoans (Late Devonian) from the Khoshyeilagh Section,Alborz Mountains (northern Iran)

A bryozoan fauna containing seven species is described from the Upper Frasnian (Upper Devonian) rocks in the Khoshyeilagh Section, Alborz Mountains (northern Iran). The studied bryozoan assemblage includes one new trepostome species, Eridotrypella alborzensis sp. nov., an additional four species identified at species level: two trepostomes, Minussina akkayaensis Volkova, 1974 and Leptotrypella inaudita Morozova, 1961, and two rhabdomesine cryptostomes, Bigeyella mariae (Morozova, 1961) and Saffordotaxis multispinata (Morozova, 1955). Furthermore, two species are described in open nomenclature: the trepostome Schulgina sp. and the rhabdomesine cryptostome Nicklesopora sp. The studied fauna shows a close similarity at the species level between northern Iran and the Altai-Sayan Folded Belt (Russia), south China, and Transcaucasia.     

Organogenesis during budding and lophophoral morphology of Hislopia malayensis Annandale, 1916 (Bryozoa, Ctenostomata)

Background  

Bryozoans represent a large lophotrochozoan phylum with controversially discussed phylogenetic position and in group relationships. Developmental processes during the budding of bryozoans are in need for revision. Just recently a study on a phylactolaemate bryozoan gave a comprehensive basis for further comparisons among bryozoans. The aim of this study is to gain more insight into developmental patterns during polypide formation in the budding process of bryozoans. Particular focus is laid upon the lophophore, also its condition in adults. For this purpose we studied organogenesis during budding and lophophoral morphology of the ctenostome bryozoan Hislopia malayensis.     

Homeomorphy in Lunostoma, a new Middle Devonian cryptostome bryozoan

A new genus and species of rhabdomesine cryptostome bryozoan, Lunostoma pulchra n. gen. n. sp., is described from the Lower Givetian (Middle Devonian) of the Eifel, Germany. It differs from all previously known rhabdomesines in having crescent-shaped structures (??scuta??) on the proximal sides of the apertures. These scuta resemble the lunaria that characterise cystoporate bryozoans, providing yet another example of homeomorphy in the Bryozoa. The function of scuta is unclear as, in contrast to lunaria, they do not project sufficiently from the apertures to constrain the everting lophophores.     

Epibiont foraminifera of Sertella frigida (Waters) (Bryozoa, Cheilostomata) from Terranova Bay, Ross Sea, Antarctica

Several arenaceous and calcareous foraminifera epibionts of Sertella frigida (Waters) (Bryozoa, Cheilostomata), collected in Terranova Bay during the 1989–90 Italian Antarctic expedition, were studied. Arenaceous species, such as Psammosphaera fusca Schulze f. adhearescens Rhumbler, Haplophragmoides canariensis d'Orbigny, Portatrochammina antarctica (Parr), and Trochammina arctica Hedley, Hurdle and Burdett, are a conspicuous component of the epifaunal community. The calcareous foraminifers encrusting S. frigida are mostly represented by Cibicides refulgens Montfort and Rosalina globularis d'Orbigny. Foraminifera were found only in the basal part of the bryozoan colonies. The presence of many juveniles provided evidence that foraminifers were reproducing at the time of sampling. Psammosphaera fusca f. adhaerescens was found exclusively inside the zooids of S. frigida. The large number of individuals associated with the bryozoan suggest that P. fusca f. adhaerescens finds optimum conditions (shelter, food, and grains for shell building) for growth inside the zooids of S. frigida. The other species occurred most commonly adhered to the trabeculae or to the zooid orifices of S. frigida. An elevated position offers a better chance to catch food particles from the overlying water column. Foraminifers could benefit also from bryozoan feeding currents. The availability of resuspended organic material could provide a more consistent source of food in a highly seasonal oligotrophic environment. Received: 8 February 1995/Accepted: 30 June 1996     

Morphological and Molecular Redefinition of Euplotes platystoma Dragesco & Dragesco‐Kernéis, 1986 and Aspidisca lynceus (Müller,1773) Ehrenberg, 1859, with Reconsideration of a “Well‐known” Euplotes Ciliate,Euplotes harpa Stein, 1859 (Ciliophora,Euplotida)

We documented the morphology, infraciliature, silverline system, and molecular data of two euplotid species isolated from China, including two populations of the poorly known Euplotes platystoma Dragesco & Dragesco‐Kernéis, 1986 and the previously well described Aspidisca lynceus (Müller, 1773 ) Ehrenberg, 1830. Based on the information available, an improved diagnosis of Euplotes platystoma is given, including: a narrow adoral zone with 44–68 membranelles, 10 frontoventral, 5 transverse, 2 left marginal and 2 caudal cirri, 11–13 dorsal kineties with 17–25 dikinetids in the mid‐dorsal row, and dorsal silverline system of the double‐eurystomus type. The Chinese population of Aspidisca lynceus closely resembles previously described populations. Phylogenetic analyses inferred from SSU rDNA sequences show that E. platystoma is closely related with E. neapolitanus, and the internal position of A. lynceus within this genus is still not robust. A reconsideration of the “well‐known” Euplotes harpa and a comparison of all SSU rDNA sequences of E. harpa in GenBank are provided. We speculate that the sequences available from GenBank under the name of E. harpa are very likely from misidentified materials, that is, the identity of the species currently associated with the SSU rDNA of this “well‐known” form in molecular databases requires further confirmation.     

Identifying monophyletic groups within Bugula sensu lato (Bryozoa,Buguloidea)

Species in the genus Bugula are globally distributed. They are most abundant in tropical and temperate shallow waters, but representatives are found in polar regions. Seven species occur in the Arctic and one in the Antarctic and species are represented in continental shelf or greater depths as well. The main characters used to define the genus include bird's head pedunculate avicularia, erect colonies, embryos brooded in globular ooecia and branches comprising two or more series of zooids. Skeletal morphology has been the primary source of taxonomic information for many calcified bryozoan groups, including the Buguloidea. Several morphological characters, however, have been suggested to be homoplastic at distinct taxonomic levels, in the light of molecular phylogenies. Our purpose was to investigate the phylogenetic interrelationships of the genus Bugula, based on molecular phylogenetics and morphology. A Bayesian molecular phylogeny was constructed using original and previously published sequences of the mitochondrial genes cytochrome c oxidase subunit 1 (COI) and the large ribosomal RNA subunit (16S). Morphological characteristics from scanning electron and light microscopy were used to confirm the clades detected by the molecular phylogeny. Our results suggest that the genus is composed of four clades, for which we provide diagnoses: Bugula sensu stricto (30 species), Bugulina (24 species), Crisularia (23 species) and the monotypic Virididentula gen. n. Ten species could not be assigned to any of those genera, so they remain as genus incertae sedis. Our findings highlight the importance of using molecular phylogenies in association with morphological characters in systematic revisions of bryozoan taxa.     

Schischcatella (Fenestrata,Bryozoa) from the Devonian of the Rhenish Massif,Germany

Abstract: The Devonian fenestrate bryozoan, Schischcatella Waschurova, 1964 , possessed colonies in the form of low, erect bifoliate fronds that grew from an encrusting sheet‐like base with autozooecia arranged in biserial, bifurcating rows. This growth habit is unique in fenestrates, which normally had unilaminate arborescent colonies. Originally, Schischcatella was described from the Lower Devonian of Tajikistan. This article describes a new species, S. heinorum sp. nov., from the Middle Devonian of the Eifel (western Rhenish Massif, Germany) with additional material from the Lower Devonian of the Kellerwald (eastern Rhenish Massif, Germany). External and internal morphologies of this bryozoan have been studied using abundant material. The growth habit of Schischcatella suggests a completely different pattern of feeding currents than that in the normal fenestrate colony. The outflow of the filtered water occurred only on edges of colonies between rami. In the absence of chimneys (areas of vertical water expelling), such a functional morphology may have restricted extension of the colony in a distal direction. The evolution of Schischcatella is apparently an example of paedomorphosis, the genus evolved from an unknown semicosciniid species by the early ontogenetic interruption of colony development and further changes in the mode of growth.     

Molecular Phylogeny and Ontogeny of a New Ciliate Genus,Paracladotricha salina n. g., n. sp. (Ciliophora,Hypotrichia)

A hypotrichous ciliate, Paracladotricha salina n. g., n. sp., was discovered in hypersaline waters (salinity about 80‰) from Qingdao, China. Its morphology and some major ontogenetic stages were studied and the phylogenetic position was estimated using standard methods. Paracladotricha salina is characterized by a flexible, more or less slender body (size 50–120 × 20–35 μm), a gonostomatid oral apparatus, one short and two long frontoventral rows, four macronuclear nodules, almost completely reduced dorsal kineties 1–3, and a loss of several parts of the ciliature, namely, the slightly shortened ciliary row of the adoral membranelles, the paroral, and the buccal, the postoral and pretransverse ventral, the transverse, and the caudal cirri. The ontogenesis is rather simple: anlage II of both filial products and anlage III of the opisthe originate de novo, while anlagen IV and V are formed within the parental rows. This combination of features requires the establishment of a new genus, Paracladotricha, which is, according to the morphological data, closely related to Schmidingerothrix and Cladotricha. The small‐subunit rRNA gene was sequenced, indicating that P. salina is, as also demonstrated by the oral apparatus, a member of the gonostomatids. We provide a first, vague hypothesis about the phylogenetic relationships of the Gonostomatidae, Cladotrichidae, and Schmidingerotrichidae. However, since molecular data of the type species of these higher taxa are lacking, their validity and relationships remain obscure.     

Euchlorocystis gen. nov. and Densicystis gen. nov., Two New Genera of Oocystaceae Algae from High‐altitude Semi‐saline Habitat (Trebouxiophyceae,Chlorophyta)

The Oocystaceae family is generally considered to contain common freshwater eukaryotic microalgae, and few are reported living in semi‐saline habitats. Our latest ecological survey in Qinghai Lake and Angzicuo Lake, both large, closed, high‐altitude, semi‐saline lakes located on the Qinghai‐Tibet plateau in China, revealed Oocystaceae species as a dominant group among plankton. Since limited knowledge exists about semi‐saline species in the Oocystaceae family, a taxonomical study was carried out using morphological and phylogenetic methods. Using this approach, four new strains of Oocystaceae were identified and successfully cultured in the lab. Molecular results correlated with morphological characters and resolved these species into at least three genera. A new genus, Euchlorocystis, with type species Euchlorocystis subsalina, is described here as having the distinctive morphology of multiple pyrenoids per chloroplast among Oocystaceae, and an independent phylogenetic position at the base of the Oocystaceae. Similarly, the genus Densicystis, with type species Densicystis glomerata, is newly proposed here as having a unique colony morphology of dozens or hundreds of little cells tightly embedded in ellipsoid to round mucilage masses. Oocystis marina, originally described from the Baltic Sea, was also identified in Qinghai Lake and Angzicuo Lake and phylogenetically positioned in the semi‐saline clade of the Oocystaceae. The result that a marine species was detected in the closed inland lakes implies a further need to reevaluate the origins of these species.     

UPPER ORDOVICIAN BRYOZOANS OF THE PIN FORMATION (SPITI VALLEY, NORTHERN INDIA)

Abstract: Twenty‐nine species of bryozoans from the Upper Ordovician–Lower Silurian Pin Formation (Spiti, India) have been identified. Eight of these are new: Trematopora minima, Ulrichostylus bhargavai, Ptilodictya exiliformis, Phaenopora ordinarius, Oanduellina himalayaica, Pesnastylus? vesiculosum, Ralfina? originalis and Pinocladia triangulata. The fossil record and facies analyses of the area investigated indicate shallow‐water conditions within the subtropical–tropical realm. The distribution pattern of fossils among the Ordovician/Silurian succession on the Northern Gondwana shelf and the influence of the Late Ordovician cooling phases on marine organisms are distinctive owing to a dramatic reduction in diversity globally. As far as the bryozoan taxa of Spiti are concerned, only one (Helopora fragilis) of the 29 species was recorded above the Ordovician/Silurian boundary. Observed bryozoan communities are very similar to faunas of Laurentia, the Baltic, Siberia and southern China of early–late Ordovician age.     

Molecular Phylogeny and Surface Morphology of Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp. (Gregarinasina,Apicomplexa) Isolated from a Deep Sea Oradarea sp. (Amphipoda) in the West Pacific

In an effort to broaden our understanding of the biodiversity and distribution of gregarines infecting crustaceans, this study describes two new species of gregarines, Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp., parasitizing a deep sea amphipod (Oradarea sp.). Amphipods were collected using the ROV Hyper‐Dolphin at a depth of 855 m while on a cruise in Sagami Bay, Japan. Gregarine trophozoites and gamonts were isolated from the gut of the amphipod and studied with light and scanning electron microscopy, and phylogenetic analysis of 18S rDNA. Thiriotia hyperdolphinae n. sp. was distinguished from existing species based on morphology, phylogenetic position, as well as host niche and geographic locality. Cephaloidophora oradareae n. sp. distinguished itself from existing Cephaloidophora, based on a difference in host (Oradarea sp.), geographic location, and to a certain extent morphology. We established this latter new species with the understanding that a more comprehensive examination of diversity at the molecular level is necessary within Cephaloidophora. Results from the 18S rDNA molecular phylogeny showed that T. hyperdolphinae n. sp. was positioned within a clade consisting of Thiriotia spp., while C. oradareae n. sp. grouped within the Cephaloidophoridae. Still, supplemental genetic information from gregarines infecting crustaceans will be needed to better understand relationships within this group of apicomplexans.     

Morphology,Ontogeny, and Molecular Phylogeny of Two Freshwater Species of Deviata (Ciliophora,Hypotrichia) from Southern China

The morphology and partial morphogenesis of two freshwater hypotrichous ciliates, Deviata brasiliensis Siqueira‐Castro et al., 2009 and Deviata rositae Küppers et al., 2007, isolated from southern China, were investigated using live observation and protargol staining. Our populations resemble the original ones in terms of their live characters and ciliary patterns. The main determinable morphogenetic features of D. brasiliensis basically correspond with those of the type population. However, the origin of anlage V for either proter or opisthe is ambiguous: whether anlage V for the proter originates from parental frontoventral row 2 (the same as in the original population) or parental frontoventral row 3 (the same as in Deviata abbrevescens) or even de novo is not clear; the anlage V for the opisthe is possibly derived from frontoventral row 3 and further migrates to frontoventral row 2, like that in D. abbrevescens. In addition, the SSU rRNA gene was first sequenced for both species. Molecular phylogenetic analyses suggest that the genus Deviata is non‐monophyletic and has a close relationship with Perisincirra paucicirrata.     

Cranial morphology and taxonomic resolution of some dolphin taxa (Delphinidae) in Australian waters,with a focus on the genus Tursiops

Phylogenetic relationships in the family Delphinidae have been widely debated. We examined 347 skulls of Tursiops, Stenella, Delphinus, Steno, Lagenodelphis, and Sousa in order to resolve the phylogenetic position of Australian species of Tursiops. Five Tursiops type specimens were included. Cranial morphology was described using 2‐dimensional (2‐D) and 3‐dimensional geometric morphometrics (3‐GM), counts and categorical data. Analyses showed a clear morphological separation of Tursiops, including type specimens, from other genera. The three Stenella species did not cluster together. Stenella attenuata clustered with Delphinus delphis, and Stenella coeruleoalba with Lagenodelphis hosei. Length and width of the skull and rostrum were important discriminators in both methods. For 3‐D data, round vs. angular posterior skull shape distinguished some genera. Taxa that overlapped in the multivariate analyses had different mean tooth counts. Our study challenges genetic studies that identified Tursiops as polyphyletic, with T. aduncus closer to S. attenuata.     

Molecular Phylogeny and Evolutionary Relationships between the Ciliate Genera Peniculistoma and Mytilophilus (Peniculistomatidae,Pleuronematida)

Peniculistoma mytili and Mytilophilus pacificae are placed in the pleuronematid scuticociliate family Peniculistomatidae based on morphology and ecological preference for the mantle cavity of mytiloid bivalves. We tested this placement with sequences of the small subunit rRNA (SSUrRNA) and cytochrome c oxidase subunit 1 (cox1) genes. These species are very closely related sister taxa with no distinct genetic difference in the SSUrRNA sequence but about 21% genetic difference for cox1, supporting their placement together but separation as distinct taxa. Using infection frequencies, M. pacificae, like its sister species P. mytili, does not interact with Ancistrum spp., co‐inhabitants of the mantle cavity. On the basis of these ecological similarities, the fossil record of host mussels, and features of morphology and stomatogenesis of these two ciliates, we argue that M. pacificae derived from a Peniculistoma‐like ancestor after divergence of the two host mussels. Our phylogenetic analyses of pleuronematid ciliates includes the SSUrRNA gene sequence of Sulcigera comosa, a Histiobalantium‐like ciliate from Lake Baikal. We conclude: (i) that the pleuronematids are a monophyletic group; (ii) that the genus Pleuronema is paraphyletic; and (iii) that S. comosa is a Histiobalantium species. We transfer S. comosa to Histiobalantium and propose a new combination Histiobalantium comosa n. comb.     

Eocene Pachynolophinae (Perissodactyla,Palaeotheriidae) from China,and their palaeobiogeographical implications

The Eocene perissodactyl family Palaeotheriidae has traditionally been considered to be a nearly endemic European group within Equoidea, but a few palaeotheres have been reported from Asia. Here, I reanalyse a maxilla containing M1–3 from the Lunan Basin, Yunnan Province, China. This element was initially assigned to a new tapiromorph species, Lophialetes yunnanensis, but is here placed in a new genus Lophiohippus within Pachynolophinae based mainly on the absence of mesostyles, the strongly oblique metalophs, the strong development of lophodonty, parastyles overlapping metastyles of preceding teeth and situated mesial to the paracone, and the fact that M3 is longer than wide and has a large and buccally deflected metastyle. Lophiohippus differs from European Anchilophus and Paranchilophus in that the parastyles are situated mesial or even slightly lingual, rather than mesiobuccal, to the paracones, and M3 is markedly relatively larger than M1. I further reanalyse Qianohippus magicus from the Shinao Basin of Guizhou Province, China, in which the complete dentition is known. Qianohippus is characterized by a molariform P2 and non‐molariform P3–4; a relatively high degree of lophodonty; the absence of mesostyles; an angular bending in the protoloph on P3‐M3 and the metaloph on M1–3 at the paraconule and metaconule, respectively; and weakly developed ‘metastylid’ on the lower cheek teeth. A cladistic analysis supports a close relationship between Lophiohippus yunnanensis and Paranchilophus, and suggests that Qianohippus is closely related to some derived pachynolophs. The appearance of the pachynolophins Lophiohippus and Qianohippus in China supports the existence of a biogeographical connection between Europe and Asia in the Middle‐Late Eocene, and the dispersal route was probably along the Tethyan microcontinents in the south.     

A Contribution to the Morphology and Phylogeny of Chlamydodon,with Three New Species from China (Ciliophora,Cyrtophoria)

Three new cyrtophorian ciliates isolated from coastal areas of China were described based on morphological and genetic data. The Chlamydodon mnemosyne‐like species Chlamydodon similis sp. n. differs from its congeners mainly by its number of somatic kineties. Chlamydodon oligochaetus sp. n. is distinguished from its congeners mainly by having fewer somatic kineties, and/or an elongated body shape. Chlamydodon crassidens sp. n. is characterized mainly by an inverted triangular body shape, a posteriorly interrupted cross‐striated band (5–6 μm wide), and a large cytostome. Moreover, we provided small‐subunit (SSU) rDNA sequences of C. similis sp. n. and C. oligochaetus sp. n. Maximum likelihood (ML) and Bayesian inference (BI) consistently placed C. similis sp. n. as a sister to C. paramnemosyne, but showed different branching position of C. oligochaetus sp. n., which may be due to a low taxon sampling in the Chlamydodontidae and/or an insufficient resolution of the marker gene at species level.